1. Field of the Invention
The present invention relates to a signal processing circuit provided on a non-contact IC card or tag such as a cash card, credit card, commutation ticket, coupon ticket, management card, ID card, driver's license, commodity management tag, and logistic management card used in a cash dispenser, electronic money system, automatic ticket gate, entry/exit management system, commodity management system, and logistic management system, and to a signal processing circuit equipped with an antenna used for transmission of an operating power and communication between the non-contact IC card or tag and a reader/writer.
2. Description of the Related Art
The non-contact IC card or tag mainly uses electromagnetic waves of High Frequency (HF) to Ultra High Frequency (UHF) bands to perform power transmission and communication. In general the HF band is known as a frequency band of 3 MHz to 30 MHz, among other things, the use of carrier of 13.56 MHz is prevailing for communication and power transmission between a non-contact IC card or tag (hereinafter, collectively referred to as “Radio Frequency Identification” RFID) and a reader/writer. The UHF band is generally known as a frequency band of 300 MHz to 3000 MHz. A carrier of 2.45 GHz is available in Japan and a frequency band of 860 MHz to 960 MHz is available in the United States and Europe for communication and power transmission between the RFID and reader/writer. A frequency of 5.8 GHz higher than the above band is allowed to be used in one-way communication from the RFID to a reader in a toll load.
Transmission and reception of electric power and information by the carrier of the HF band between the RFID and reader/writer is mainly performed in such a manner that a spiral antenna provided on the RFID is interlinked with magnetic field outputted from the antenna of the reader/writer to cause the spiral antenna to induce an electric power and signal current. On the other hand, the supply of electric power to RFID and the transmission and reception of information by the carrier of the UHF band are mainly performed in such a manner that a dipole antenna or a patch antenna provided on the RFID receives electric field from a reader/writer and the like to induce an electric power and signal current.
For the foregoing frequency used in communication between the above RFID and the reader/writer or an equivalent (for example, only a reader), there are regulations with regard to the output of transmission of electromagnetic waves stipulated by the administration. For this reason, it is prohibited to radiate electromagnetic waves exceeding the regulated value from for example the RFID without permission from an organization in charge of this matter. Thus, in a communicating between the RFID and an identifying device such as a reader/writer (also called external device, transmission/reception terminal station unit, base station for the RFID according to applications, hereinafter referred to as “external device”) by using the carrier of the HF band, a distance between which is obliged to be short because of a small output of the HF band. On the other hand, in communicating between the RFID and the external device by using the carrier of the UHF band, a distance between which can be extended because the output of the UHF band can be increased.
Under these circumstances, the following patent document 1 has proposed a hybrid-type IC card on which a near magnetic field-type module using the carrier of the HF band and a radio-type module using the carrier of the UHF band are mounted. A non-contact IC card similar to the above has been disclosed in the following patent document 2 and a communication terminal device similar to the above is also disclosed in the following patent document 3.
[Patent Document 1] JP-A No. 240899/2004.
[Patent Document 2] JP-A No. 290229/1993.
[Patent Document 3] JP-A No. 297499/2004.